The present invention relates to a miter saw, and more particularly to a miter saw provided with a light-projecting device such as a laser oscillator for projecting a projection line indicative of a cutting position of a saw blade on a workpiece.
FIG. 17 illustrates a conventional miter saw. As shown in FIG. 17, the miter saw includes a base 702, a fence 703, a turntable 710, a cutting unit 720, a support unit 730, and a laser oscillator 751. The turntable 710 is rotatably mounted on the base 702 for supporting thereon a workpiece W in cooperation with the base 702. The fence 703 is secured to the base 702 and extends across the turntable 710. The fence 703 has a positioning surface to which the workpiece W is abutted for positioning the workpiece W. The cutting unit 720 has a circular saw blade 721. The support unit 730 movably supports the cutting unit 720 at a position above the turntable 710. The laser oscillator 751 is mounted on the support unit 730. The laser oscillator 751 emits a laser beam onto the workpiece W in order to indicate the position of the tip of the blade 721 and its extension position as a line on the surface of the workpiece W. The laser oscillator 751 is fixed to a given position so that a part of or entire laser beam can travel below the circular saw blade 721 and illuminate the surface of the workpiece W without being interrupted by the blade 721 when the blade 721 is at its uppermost position. The turntable 710 may be rotated to bring the laser beam into alignment with a marker (indicating a cutting line) already drawn on the workpiece W. Thus, the miter saw can cut the workpiece W precisely along the marker. A miter saw of this type is disclosed in for example laid open Japanese Patent Application Publication No. 2000-225603.
If the workpiece W has a rectangular cross-section as shown in FIG. 17, a user who stands in front of the miter saw can easily see whether or not the laser beam irradiated on an upper surface of the workpiece W is aligned with the cutting line marker delineated on the upper surface of the workpiece W. On the other hand, if the workpiece W has such an irregular cross-section as illustrated in FIG. 18, the user cannot provisionally draw a cutting line marker on the upper surface of the workpiece W. In the latter case, the user draws a cutting line marker M2 or M3 (see FIG. 7) on a vertical side of the workpiece W in contact with the fence 703. Then, the user rotates the turntable 720 and brings the blade 721 into alignment with the line marker M2 or M3 before the user starts cutting the workpiece W. To align the blade 721 with the line marker M2 or M3, the user needs to walk around to the back of the miter saw and bow or stoop his head to see both the line marker M2 or M3 and the laser beam at the rear vertical side of the workpiece W. This would be troublesome, lowering the efficiency of sawing the workpiece W.